FIELD OF THE INVENTION

This invention relates to novel paint compositions containing water glass which show excellent storage stability and handling properties.

BACKGROUND OF THE INVENTION

Water glass is the common name given to water soluble silicates containing varying proportions of an alkali metal or quaternary ammonium ion and silica.

The use of water glass in paints is widespread, however it is also associated to limitations in the handling and application properties due to the tendency to fast increase of viscosity and strong gelation of the paints during storage.

Control over the rheology of paints is critical to achieve good handling and application properties. In“Rheology Reviews 2005, pp 173 - 240” an extensive description of how the commercial viability and success of paints and coatings are linked to the right rheological properties of the products is reported. Easiness of stirring, loading and brushing or rolling of a paint are directly related to its viscosity. The time-dependent shear thinning effect, referred as thixotropy, gives a good estimation of how strong the interactions between the components of a paint during shearing are and indicates, for example, how much effort has to be invested to achieve optimal mixing. The gel character of a paint is given by its elastic module, which is an excellent descriptor of the strength of the colloidal interactions between the paint components under very low shear stress, as it is the case during storage. High elastic module is undesired since paint appearance and workability would be gel-like.

In order to improve the rheological properties of paints containing water glass, the use of specific additives is a common practice in the industry.

DE-19925412 describes paint compositions containing water soluble silicates. The use of water soluble quaternary organic amines is described to have a beneficial effect on the stabilization of the paint viscosity during storage. The viscosity of the claimed paint as described in the invention related examples increased by a factor of 1.8 after being stored for 30 days at 40 °C. No information about the final viscosity value and about the thixotropy and gel character of the paint after storage is provided.

WO-2008/037382 describes the use of mixtures comprising one or more amines with a molecular weight between 120 and 10000 and one or more alkyl siliconates for stabilization of the viscosity of water glass containing paints. The viscosity of the claimed paint compositions as described in the invention related examples increased by a factor of 1.9 after being stored for 28 days at 30 °C and reached a final value of 3600 mPas. No information about the thixotropy and gel character of the paint after storage was provided.

WO-02/00798 describes paints containing a maximum of 2 percent by weight of water glass. It is ambiguous either the term water glass refers to the active or to the aqueous silicate solution. The claimed paint compositions are said to show excellent stability and handling properties similar to those of polymer dispersion paints, but no rheological data are reported to support that claims. Furthermore, the use of stabilizing additives is not explicitly described.

It has been observed that paint compositions comprising water glass will increase their viscosity, thixotropy and gel character during storage. This is an undesired effect since it will impede the handling properties of such paint compositions.

Besides minor viscosity change and moderate final viscosity values after storage, low thixotropic behavior and weak gel character are the key rheological properties needed in order to achieve paint compositions containing water glass which show excellent storage stability and are easy to handle and to use. There is a lack of paint compositions containing water glass showing such rheological properties. It was the object of this invention to provide additives for water glass containing paint compositions that will mitigate the increase in the viscosity, thixotropy and gel character during storage of such paint compositions. Surprisingly, it has now been found that aqueous paint compositions according to the invention have excellent storage stability and handling properties.

In a first aspect, the present invention relates to an aqueous paint composition comprising:

1 ) 0.01 to 5 wt.-% of a copolymer comprising

(A) from 50 mol-% to 98 mol-% of repeating anionic structural units

comprising at least one carboxyiate group,

and

(B) 2 mol-% to 50 mol-% repeating units according to formula (B1 )

wherein

R ¹¹ , R ¹² , R ¹³ , are independently selected from the group consisting of

H, methyl, ethyl,

R ² and R ³ are independently selected from the group consisting of

H, methyl, ethyl or phenyl,

R ⁴ is selected from H or an alkyl group with 1 to 4 carbon atoms,

X is selected from O, CH2O or CH2CH2O,

Y is selected from an alkylene group with 1 to 28 carbon atoms or a phenylene group,

m is an integer from 1 to 500,

n is an integer from 0 to 500; and

m + n ³ 5, ) 0.01 to 5.0 wt.-% of water glass, 3) 3 to 25 wt.-% of an organic polymeric binder,

4) 10 to 70 wt.-% of pigments and/or fillers,

5) 20 to 85 wt.-% of water.

In a second aspect, this invention relates to the use of a copolymer as defined under 1 ) above to diminish the increase of viscosity, thixotropy and gel character upon storage of an aqueous paint composition, comprising the components 2), 3), 4) and 5) as defined above.

In one preferred embodiment, the composition according to the invention comprises up to 10 wt.-% of further additives.

In another preferred embodiment, the composition according to the invention comprises 30 to 60 wt.-% water.

Copolymers derived from the mentioned structural units (A) and (B) have been previously described. DE-10063291 teaches the use of such copolymers as flow agents for anhydrite-based flow screeds. EP-1179517 describes copolymers derived from the structural units (A) and (B) as cement dispersants.

In contrast to water glass, both anhydrite and cement are solid materials which are dispersed but not dissolved in water and therefore the interactions between the polymers and the soluble silicates are expected to be completely different than those between the polymers and the anhydrite and cement particles. Surprisingly, it was found that the above mentioned copolymers showed a highly effective stabilizing effect on the rheological properties of paints containing water glass.

Units (A)

In a preferred embodiment, the molar proportion of units (A) is 55 mol-% to

95 mol-%, more preferred from 60 mol-% to 90 mol-%. In a preferred embodiment, the repeating anionic structural unit results from the incorporation of monomers according to formula (A1 ):

wherein

R ¹⁵ and R ³ are selected from the group consisting of H, methyl, ethyl, and

C(0)0 Z ⁺ ;

X, Y are selected from the group consisting of a covalent bond, O, CH2,

C(0)0, OC(O), C(0)NR ³ or NR ³ C(0);

M is selected from the group consisting of a covalent bond,

-[C(0)0-CH2-CH2]k-, a linear or branched alkylene group with 1 to 6 carbon atoms, a linear or branched, mono- or polyunsaturated alkenylene group with 2 to 6 carbon atoms, a linear mono- hydroxyalkylene group with 2 to 6 carbon atoms or a linear or branched di-hydroxyalkylene group with 3 to 6 carbon atoms;

k is an integer from 1 to 5; and

2+ is selected from the group consisting of

an organic ammonium ion [HNR ⁵ R ⁶ R ⁷ ] ⁺

R ⁵ , R ⁶ , R ⁷ are independently hydrogen, a linear or branched alkyl group with 1 to 22 carbon atoms, a linear or branched, mono- or polyunsaturated alkenyl group with 2 to 22 carbon atoms, a Ce to C22 alkylamidopropyl group, a linear mono-hydroxyaikyl group with 2 to 10 carbon atoms or a linear or branched di-hydroxyalkyl group with 3 to 10 carbon atoms, and wherein at least one of R ⁵ , R ⁶ and R ⁷ is not hydrogen. In one preferred embodiment,

or 1 /3 AG ⁺⁺ , more preferably most preferably Na ⁺ .

in another preferred embodiment, Z ⁺ is selected from the group consisting of monoalkylammonium, dialkylammonium, trialkylammonium and

tetraalkylammonium salts, in which the alkyl substituents may independently of one another be (Ci to C22)-alkyl radicals or (C2 to Cio)-hydroxyalkyl radicals.

In a preferred embodiment, unit (A) is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, carboxyethyiacrylic acid, carboxyethylacrylic acid oligomers, 2-propylacrylic acid, 2-ethylacrylic acid, maleic acid and their respective salts. In one preferred embodiment, the salts are with the cations selected from the group consisting of: NH ₄ +, Li+, Na+, K+, ½ Ca++, ½ Mg++,

½ Zn++, or V3 AI+++, monoalkylammonium, dialkylammonium, trialkylammonium and/or tetraalkylammonium more preferably NH4+, Li+, Na+ or K+, most preferably Na+.

In one embodiment, the polymer comprises at least one repeating unit according to formula (A1 ). In another embodiment, the polymer comprises two or more different repeating units according to Formula (A). Such repeating units according to formula (A1 ) may have different Z ⁺ counterions.

The repeating units according to formula (1 ) have a degree of neutralisation of between 0 mol-% and 100 mol-%. In a preferred embodiment, the repeating units according to formula (A1 ) have a degree of neutralisation of from 50.0 to

100 mol-%, preferably from 80 mol-% to 100 mol-%, more preferably from 90.0 to 100 mol-%, even more preferably from 95.0 to 100 mol-%. Particular preference is being given to a degree of neutralisation of more than 80 mol-%, more preferably more than 90 mol-%, even more preferably more than 95 mol-%.

Units (B)

In a preferred embodiment, the polymer 1 ) comprises from 5 mol-% to 45 mol-%, preferably from 10 mol-% to 40 mol-% of repeating structural unit (B). In a preferred embodiment, the repeating structural unit (B) comprises one aikylene oxide unit of the formula -(CHR2-CHR3-0)m-, wherein all (CHR2-CHR3O) units are the same species, i.e. a homopolymer.

In another preferred embodiment, the repeating structural unit (B) comprises two or more different aikylene oxide units of the formula -(CHR2-CHR3-0)m-, wherein the (CHR2-CHR3O) units are selected from different species, i.e. a copolymer. The distribution of the different aikylene oxide units -(CHR2-CHR3-0) _m -can be random, alternating or block-wise (i.e. block copolymer). m is preferably a number from 5 to 200, more preferably 10 to 100.

In a preferred embodiment, the polymer comprises at least one repeating structural unit (B) wherin R ¹¹ , R ¹² and R ¹³ are H, and X is O. Such compounds are known as polyaikylene glycol vinylether.

In a preferred embodiment, the polymer comprises at least one repeating structural unit (B) wherin R ¹¹ , R ¹³ are H, R ¹² is CH3 and X is -CH2-CH2-O-. Such compounds are known as polyaikylene glycol isoprenylether.

In a preferred embodiment, the polymer comprises at least one repeating structural unit (B) wherin R ¹¹ , R ¹² and R ¹³ are H, and X is -CH2-O-. Such compounds are known as polyaikylene glycol allylether.

In a preferred embodiment, the polymer comprises at least one repeating structural unit (B) wherin R ¹¹ , R ¹³ are H, R ¹² is CH3 and X is -CH2-O-, Such compounds are known as polyaikylene glycol methaliylether.

In a preferred embodiment, the repeating structural unit (B) comprises at least one aikylene oxide, a substituted arylen group or a non-substituted arylen group unit -(Y-O)n-. In a preferred embodiment, the repeating structural unit (B) comprises two or more different aikylene oxide, a substituted arylen or a non-substituted arylen units -(Y-O)n-. The distribution of the different -(Y-O)n- units can be random, alternating or block-wise (i.e. block copolymer).

In a preferred embodiment, the repeating structural unit (B) comprises at least one -(CHR2-CHR3-0)m- unit and at least one -(Y-O)n- unit. This means that both m and n are different from zero. In a preferred embodiment, the repeating structural unit (B) comprises two or more different -(CHR2-CHR3-0)m- unit and comprises two or more different -(Y-O)n- units. The distribution of the different

-(CHR2-CHR3-0)m- and -(Y-O)n- units can be random, alternating or block-wise (i.e. block copolymer).

In one preferred embodiment, in formula B1 the -(CHR2-CHR3-0)m- unit means propylene oxide units and the -(Y-O)n- means ethylene oxide units. The distribution of the propylene oxide units and ethylene oxide units can be random, alternating or block-wise (i.e. block copolymer), m preferably is from 1 to 500 and n preferably is from 1 to 500

In one preferred embodiment, the repeating structural unit (B) comprises propylene oxide units and ethylene oxide units with a molar fraction of ethylene oxide > 50 %, more preferably > 95 % based on the sum total (100 %) of ethylene oxide and propylene oxide units.

In another preferred embodiment, n is 0. In this embodiment the repeating structural unit -(CHR2-CHR3-0)m- is preferably either an ethoxide group (R ² ,

R ³ = H) or it is a propoxide group (R ² = CH3 and R ³ = H or R ³ - CH ₃ and R ² = H).

In a preferred embodiment, m is from 2 to 500, preferably from 5 to 350 and more preferably from 15 to 150. If n is different from zero, it preferably is 1 to 500, more preferably 5 to 350 and most preferably 15 to 150.

In a preferred embodiment, m + n > 10, more preferably m + n > 20.

In a preferred embodiment, X is selected from O or CH2O. In a preferred embodiment, Y is selected from CH2O, CH2-CH2-O- phenylene or CH2-CHR-O- wherein R is an alkyl group with 1 to 26 carbon atoms.

Optional units:

In a preferred embodiment, the copolymer 1 ) may comprise units (A) and (B) so to add up to 100 mol-%.

In another preferred embodiment, the copolymer 1 ) may comprise other units than (A) and (B). These other units are referred to as optional units.

In a preferred embodiment, the optional unit result from the incorporation of a monomer selected from the group consisting of N-vinylformamide,

N-vinylacetamide, N methyl-N-vinylformamide, N-methyl-N-vinylacetamide, N-vinyl-2-pyrrolidone (NVP), N vinylcapro!actam, vinylacetate, methylvinylether, ethylvinylether, methylallylether, ethylmethallylether, styrol, acetoxystyrol, methy!methallylether, ethylallylether, tert-butylacrylamide, N,N-diethylacrylamide, N,N-dimethylacry!amide, N,N-dimethylmethacrylamide, N,N-dipropylacryiamide, N-isopropylacrylamide, N-propyiacrylamide, acrylamide, methacrylamide, methylacrylate, methylmethacrylate, tert-butylacrylate, tert-butylmethacrylate, n-butylacrylate, n-butylmethacrylate, laurylacry!ate, laurylmethacrylate,

behenylacrylate, behenyimethacrylate, cetylacrylate, cetylmethacrylate,

stearylacrylate, stearylmethacrylate, tridecylacrylate, tridecylmethacrylate, polyethoxy-(5)-methacrylate, polyethoxy-(5)-acrylate, polyethoxy-(10)- methacrylate, polyethoxy-(10)-acrylate, behenylpolyethoxy-(7)-methacrylate, behenylpolyethoxy-(7)-acrylate, behenylpolyethoxy-(8)-methacrylate, behenylpoly- ethoxy-(8)-acrylate, behenylpolyethoxy-(12)-methacrylate, behenylpoly-ethoxy- (12)-acrylate, behenylpolyethoxy-(16)-methacrylate, behenylpolyethoxy-(16)- acrylate, behenylpolyethoxy-(25)-methacrylate, behenylpolyethoxy-(25)-acrylate, laurylpoly-ethoxy-(7)-methacrylate, laurylpolyethoxy-(7)-acrylate, laurylpolyethoxy- (8)-methacrylate, laurylpolyethoxy-(8)-acrylate, laurylpolyethoxy-(12)-methacrylate, laurylpolyethoxy-(12)-acrylate, laurylpolyethoxy-(16)-methacrylate,

laurylpolyethoxy-(16)-acrylate, laurylpolyethoxy-(22)-methacry!ate, laurylpolyethoxy-(22)-acrylate, laurylpolyethoxy-(23)-methacrylate, laurylpoiyethoxy-(23)-acrylate, cetylpolyethoxy-(2)-methacrylate, cetylpolyethoxy- (2)-acrylate, cetylpolyethoxy-(7)-methacrylate, cetylpolyethoxy-(7)-acrylate, cetylpolyethoxy-(10)-methacrylate, cetylpoiyethoxy-(10)-acrylate, cetylpolyethoxy- { 12)-methacrylate, cetylpolyethoxy-( 12)-acrylate cetylpoly-ethoxy-( 16)- methacrylate, cetylpolyethoxy-( 16)-acrylate cetylpolyethoxy-(20)-methacrylate, cety!polyethoxy-(20)-acrylate, cetylpoiyethoxy-(25)-methacrylate, cetylpolyethoxy- (25)-acrylate, cetylpolyethoxy-(25)-methacryiate, cetylpolyethoxy-(25)-acrylate, stearylpolyethoxy-(7)-methacrylate, stearylpolyethoxy-(7)-acrylate, stearylpoly- ethoxy-(8)-methacrylate, stearylpolyethoxy-(8)-acryiate, stearylpolyethoxy-(12)- methacrylate, stearylpolyethoxy-(12)-acrylate, stearylpolyethoxy-(16)- methacryiate, stearylpoiyethoxy-(16)-acrylate, stearylpolyethoxy-(22)- methacrylate, stearylpoiy-ethoxy-(22)-acrytate, steary!polyethoxy-{23)- methacrylate, stearylpolyethoxy-(23)-acrylate, stearylpo(yethoxy-(25)- methacrylate, stearylpolyethoxy-(25)-acrylate, tridecylpolyethoxy-(7)-methacryjate _[ tridecylpolyethoxy-(7)-acrylate, tridecylpotythoxy-(10)-methacrylate,

tridecylpolyethoxy-(10)-acrylate, tridecylpolyethoxy-(12)-methacrylate,

tridecylpolyethoxy-{12)-acrylate, tridecylpo!yethoxy-(16)-methacrylate,

tridecylpolyethoxy-(16)-acrylate, tridecylpolyethoxy-(22)-methacrylaie, tridecylpoly- ethoxy-{22)-acrylate, tridecylpolyethoxy-{23)-methacrytate, tridecylpolyethoxy-(23)- acrylate, tridecytpoly-ethoxy-(25)-methacrylate _! tridecylpolyethoxy-(25)-acrylate, methoxypolyethoxy-(7)-methacrylat6, methoxy-polyethoxy-(7)-acrylate,

methoxypoly-ethoxy-{12)-methacrylate, methoxypolyethoxy-(12)-acrylate, methoxypolyethoxy-(16)-methacrylate, methoxypolyethoxy-(16)-acrylate, methoxypoiyethoxy-(25)-methacrylate, methoxy-polyethoxy-(25)-acrylate,

In the following, the method of making polymer 1 ) is described.

In a preferred embodiment, the polymer is obtained by polymerization of at least one structural unit (A), of at least one structural unit (B) and optionally at least one optional monomer. In a preferred embodiment, the above monomers are dissolved or dispersed in a polar solvent. The polymerisation is preferably initiated by the addition of a radical initiator.

In a preferred embodiment, the monomer according to Formula (A1 ) can be neutralized by using gaseous ammonia, ammonia hydroxide solution, morpholine, monoaikylamine, dialkylamine, trialkylamine, tetraalkylammonium salts, 2-amino- 2-methyl-1 -propanol, N-methyi-D-glucamine, N,N-dimethyl-D-glucamine sodium hydrogen carbonate, sodium carbonate, sodium hydroxide, potassium hydrogen carbonate, potassium carbonate, potassium hydroxide, lithium hydrogen carbonate, lithium carbonate, lithium hydroxide, preferably sodium hydroxide, 2-amino-2-methyl-1 -propanol, N-methyi-D-glucamine and N,N-dimethyl-D- glucamine.

In a preferred embodiment the synthesis of the polymer is carried out by radical polymerization in a polar solvent or a polar solvent mixture. Preferably the polar solvent or a polar solvent mixture has a boiling point between 60 °C and 130 °C, preferably between 60 °C and 120 °C and more preferably between 70 °C and 110 °C.

In a preferred embodiment the radical polymerization is carried out in a polar solvent comprising water.

In a preferred embodiment the polymerization is a radical precipitation

polymerization which is carried out in a polar solvent mixture comprising

I) water and

II) a further compound.

In a preferred embodiment the compound II) is polar and organic.

In a more preferred embodiment the compound II) is selected from the group consisting of poiar alcohols, ethers and ketones. In a still more preferred embodiment, the compound II) is selected from the group consisting of methanol, ethanol, 1 -propanol, 2-propanol, 2-methyl-2-propanol,

1 -butanol, 2-butanol, dimethyl ketone, diethyl ketone, pentan-2-one, butanone, tetrahydro pyrane, tetrahydro furane, 2-methyl-tetrahydro furane, 1 ,3-dioxane,

1 ,4-dioxane, preferably 2-propanol, 2-methyl-2-propanol, dimethyl ketone, tetrahydro furane, 2-methyl-tetrahydro furane, more preferably 2-methyl-2- propanol and dimethyl ketone.

In a preferred embodiment, the polymerization reaction is initiated by a radical initiator compound selected from the group of azo-initiators (e.g. azo-bis-iso butyro nitrile, 2,2'-azobis(4-methoxy-2.4-dimethyl valeronitrile), 2,2’-azobis(2.4- dimethyl valeronitrile), dimethyl 2,2’-azobis{2-methylpropionate), 2,2’-azobis(2- methylbutyronitrile), 1 ,T-azobis(cyclohexane-1-carbonitrile) Oder 2,2'-azobis[N-(2- propenyl)-2-methyl-propionamide]), peroxides (e.g. dilauryl peroxide,

tert.-butylhydro peroxide, di-tert.-butyl peroxide, tri phenyl methyl hydroperoxid, benzoyiperoxid) or persulfates (e.g. Ammonium persulfate, Sodium persulfate, Potassium persulfate). In a preferred embodiment, the initiation of the

polymerization starts in a temperature interval between 30 °C up to 110 °C, preferably between 40 °C up to 90 °C during 30 minutes to serial hours.

In a preferred embodiment, the polymer 1 ) has a weight average molecular weight of at least 1000 g/mol, preferably from 1000 g/mol to 500,000 g/mol.

Water glass

The term water glass as component (2) of the present invention denotes water soluble silicates. The indicated concentration refers to solids content of the water glass. The composition of water glass is typically defined by the molar ratio of silica to alkali metal or to quaternary ammonium ion. In paint applications, water glass is typically incorporated as aqueous solution of concentrations lower than 40 wt.-% and molar ratio >3.2. Preferred salts are alkali metals, especially preferred are potassium and lithium salts. In a preferred embodiment, the amount of water glass is from 0.1 to 4.5 wt.-%, more preferred from 0.5 to 4 wt.-%. Still more preferably, the minimum content of water glass is 1 wt.-%. Organic polymeric binder

The organic polymeric binder as component 3) of the present invention are polymers and/or copolymers based on at least one olefinically unsaturated monomer. The binder cements the pigment particles into a uniform paint film and also makes the paint adhere to the surface.

Preferred olefinically unsaturated monomers are for example:

vinyl monomers, such as carboxylic esters of vinyl alcohol, as for example vinyl acetate, vinyl propionate and vinyl esters of isononanoic acid or isodecanoic acid, aryl-substituted olefins, such as styrene and stilbene, olefinically unsatutrated carboxylic esters, such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, and aiso the corresponding methacrylic esters, olefinically unsaturated dicarboxylic esters, such as dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, dipentyi maleate, dihexyl maleate, and di-2-ethyl hexyl maleate, olefinically unsaturated carboxylic acids and dicarboxylic acids, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid, and their sodium, potassium , and ammonium salts, olefinically unsaturated sulfonic acids and phosphonic acids and their alkali metal and ammonium salts, such as acryiamidomethylpropanesulfonic acid and its alkali metal and ammonium salts, alkylammonium and hydroxyalkylammonium salts, and allylsulfonic acid and its alkali metal and ammonium salts,

acryloyioxyethylphosphonic acid and its ammonium and alkali metal salts, and also the corresponding methacrylic acid derivatives, olefinically unsaturated amines, ammonium salts, nitriles and amides, such as dimethylaminoethyl acrylate, acryloyloxyethyltrimethylammonium halides, acrylonitrile,

N-methyiacrylamide, and also the corresponding methacrylic acid derivatives, and vinyl methylaceta m id e .

The denoted concentration refers to the solids content of polymer. The film forming polymers are preferably incorporated in the paints according to the invention in form of aqueous dispersions. Pigments

Suitable pigments and fillers as component 4) of the present invention are white inorganic pigments and fillers such as, for example, titanium dioxides, calcium carbonates, talc, kaolin, barium sulfates, zinc sulfides, and zinc oxides. Preference is also given to the use of mixtures of the stated white inorganic pigments. One particularly preferred mixture of inorganic white pigments comprises titanium dioxide, calcium carbonate and talc;

colored inorganic pigments such as, for example iron oxides, magnetite, manganese iron oxides, chrome oxides, ultramarine, nickel- or chrome antimony titanate, manganese titanium rutile, cobalt oxides, mixed oxides of cobalt and aluminium, mixed-phase pigments with rutile structures, rare earths sulfides, nickel- or zinc cobalt spinel, iron chrome spinel with copper zinc and manganese, bismuth vanadates, can be also used. Specially preferred are the colored inorganic pigments corresponding to the color indexes Pigment Yellow 184, Pigment Yellow 53, Pigment Yellow 42, Pigment Brown 42, Pigment Red 101 , Pigment Blue 28, Pigment Blue 36, Pigment Green 50, Pigment Green 17, Pigment Black 1 1 , Pigment Black 33;

organic pigments such as, for example, carbon blacks, monoazo- and

disazopigments, specially the color index pigments Pigment Yellow 1 , Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 17, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 81 , Pigment Yellow 83, Pigment Yellow 87, Pigment Yellow 97, Pigment Yellow 1 11 , Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 128, Pigment Yellow 155, Pigment Yellow 174, Pigment Yellow 176, Pigment

Yellow 191 , Pigment Yellow 213, Pigment Yellow 214, Pigment Red 38, Pigment Red 144, Pigment Red 214, Pigment Red 242, Pigment Red 262, Pigment

Red 266, Pigment Red 269, Pigment Red 274, Pigment Orange 13, Pigment

Orange 34 or Pigment Brown 41 ; b-Naphthol- und Naphthol AS-pigments, specially the color index pigments Pigment Red 2, Pigment Red 3, Pigment Red 4, Pigment Red 5, Pigment Red 9, Pigment Red 12, Pigment Red 14, Pigment Red 53:1 , Pigment Red 112, Pigment Red 146, Pigment Red 147, Pigment Red 170, Pigment Red 184, Pigment Red 187, Pigment Red 188, Pigment

Red 210, Pigment Red 247, Pigment Red 253, Pigment Red 256, Pigment Orange 5, Pigment Orange 38 or Pigment Brown 1 ; lake azo- and metal complex pigments, specially the color index pigments Pigment Red 48:2, Pigment

Red 48:3, Pigment Red 48:4, Pigment Red 57:1 , Pigment Red 257, Pigment Orange 68 Oder Pigment Orange 70; benzimidazolone pigments, especially the color index pigments Pigment Yellow 120, Pigment Yellow 151 , Pigment

Yellow 154, Pigment Yellow 175, Pigment Yellow 180, Pigment Yellow 181 , Pigment Yellow 194, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208, Pigment Violet 32, Pigment Orange 36, Pigment Orange 62, Pigment Orange 72 or Pigment Brown 25; isoindolinon- and isoindoline pigments, specially the color index pigments Pigment Yellow 139 Oder Pigment Yellow 173; phthalocyanine pigments, especially the color index pigments Pigment Blue 15, Pigment Blue 15:1 , Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Blue 15:6, Pigment Blue 16, Pigment Green 7 oder Pigment Green 36; anthanthrone-, anthraquinone-, quinacridone-, dioxazine-, indanthrone-, perylene-, perinone- und thioindigo pigments, especially the color index pigments Pigment Yellow 196, Pigment Red 122, Pigment Red 149, Pigment Red 168, Pigment Red 177, Pigment Red 179, Pigment Red 181 , Pigment Red 207, Pigment

Red 209, Pigment Red 263, Pigment Blue 60, Pigment Violet 19, Pigment

Violet 23 or Pigment Orange 43; triary!carbonium pigments, especially the color index pigments Pigment Red 169, Pigment Blue 56 or Pigment Blue 61 ;

diketopyrrolopyrrole pigments, especially the color index pigments Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 270, Pigment

Red 272, Pigment Orange 71 , Pigment Orange 73 or Pigment Orange 81.

Further additives

The composition according to the invention may comprise further additives. This denotes customary auxiliaries which may be used in the paint composition of the present invention, such as wetting agents, dispersants, defoamers, rheological additives, biocides, fungicides and algicides, film-forming assistants, pH-adjusting agents and stabilizers.

Suitable wetting agents and dispersants are preferentially homopolymers and copolymers of acrylic acid, methacrylic acid, maleic acid, fumaric acid and the sodium, potassium, and ammonium salts thereof; poiyphosphonates and phosphonic acid derivatives; alkylphenolethoxyiates, fatty acid and fatty alcohol derivatives, especially the ethoxylation products; ethylene oxide / propylene oxide homo- and block-copolymers and polysiloxane ethers.

Suitable defoamers are mineral oil defoamers, silicone defoamers, or defoamers based on polyalkylene glycol ethers. Defoaming components of the stated defoamer classes are hydrophobic particulate solids such as hydrophobically modified silica, fatty acid salts of divalent and trivalent cations such as aluminium stereate, amide waxes such as ethylenbisstearylamide, and silicone resins.

Suitable rheological additives are starch- and cellulose derivatives, hydrophobic modified ethoxylated urethanes (HEUR) thickeners, alkali-soluble acrylate thickeners, xanthan gums, clays, polymers based on acrylamide methylpropane sulfonic acid, or pyrogenic silica.

Suitable biocides are formaldehyde and formaldehyde donor compounds such as dihydroxy-2, 5-dioxahexane, chlormethylisothiazolinone, benzylisothiazolinone, benzimidazolinone, and bronopol. To prevent infestation by fungi and algae, particularly following application of the paint to exterior walls, facades, shingles, and metallic and plastic parts in the exterior sector, film preservatives may be added to the paints. Suitable examples include diuron, carbendazim,

octylisothiazolinone, dichlorooctylisothiazolinone, zinc pyrithione, terbutryn, and irgarol.

Suitable pH-adjusting agents are alkali metal hydroxides or ammonium hydroxide or organic amines. Specially preferred are lithium, sodium and potassium hydroxide. Among the organic amines, 2-amino-2-methyl-1 -propanol, N-methyl-D- glucamine and N,N-dimethyl-D-glucamine are specially preferred.

Suitable film-forming assistants are substances which lower the minimum film formation temperature to down to below 5 °C, such as, for example, white spirit, methylpropylene glycol, methyldipropylene glycol, methyitripropylene glycol, butyl glycol, butyldipropylene glycol, and butyltripropylene glycol, diethylene glycol benzoate, trimethyipentane-1 ,3-dio! monoisobutyrate, isodecylbenzoate, iso no nyl benzoate, monoethylene glycol, and monopropylene glycol monooleate, and lactic esters of alcohols having 6 to 30 carbon atoms.

Suitable additional additives which contribute to the stabilization of the rheological properties of the invention related paint compositions are N-alkyl-N,N-dimethyl-D- glucamine quats, where the alkyl rest corresponds to a linear or branched aliphatic carbon chain with 1 to 12 carbon atoms, particularly preferred with 1 to 4 carbon atoms, most specially preferred when the alkyl rest is a methyl group.

In case that the paint composition according to this invention contains one or more auxiliaries as described under component (v), following concentrations are preferred for each of the different classes of auxiliaries:

up to 10 wt.-% of wetting agents and/or dispersants

up to 5 wt.-% of defoamers

up to 5 wt.-% of rheological additives

up to 5 wt.-% of biocides, fungicides and/or algicides

up to 5 wt- of film forming assistants

up to 10 wt.- of pH-adjusting agents

up to 5 wt.- of stabilizers.

In an preferred embodiment, the inventive composition is free from biocides, fungicides and/or algicides.

In a preferred form of the invention, the pH of the paint composition is adjusted to a value from 10 to 12.

In a preferred form of the invention, the concentration of biocides, fungicides and/or algicides is < 0.01 wt.-%. Specially preferred is a total concentration of isothiazolinones < 0.01 wt.-%. Most particularly preferred is a total concentration of isothiazolinones < 0.0015 wt.-%. Also pari of the present invention is a method to prepare the paint composition according to this invention. According to the method, the copolymer (1 ) is added to water and dissolved or mixed with water as an already aqueous polymer solution. Auxiliaries (5), such as wetting agents, dispersants, defoamers, rheological additives, biocides, fungicides and algicides, film-forming assistants, pH-adjusting agents and/ or stabilizers are optionally added. Afterwards the pigments and/or fillers (4) are added and finely dispersed, followed by the addition of the film forming polymer (3), preferably in form of an aqueous dispersion, the water glass (2), preferably as an aqueous solution of concentration lower than 40 wt.-% and molar ratio >3.2, and optionally auxiliaries . Finally the pH is preferably adjusted to a value between 10 and 12, by eventual addition of pH-adjusting agents if required, and the final solids concentration is adjusted by addition of water (5).

Also part of the present invention is the use of the paint composition containing water glass for outdoor, indoor, fagade, roof and floor applications.

The paint compositions according to the present invention show excellent storage stability. Only slight increase of the viscosity is observed after warm storage, which remains at low value. Furthermore, the excellent rheological profile of the paint composition after storage is confirmed by moderate thixotropic behavior and gel-character of the paint, which ensures excellent workability and handling properties of the paint.

In this document, including in all embodiments of all aspects of the present invention, the following definitions apply unless specifically stated otherwise.

All percentages are by weight (w/w) of the total composition.“wt.-%” means percentage by weight;“vol.-%” means percentage by volume;“mol-%” means percentage by mole. All ratios are weight ratios. References to‘parts ¹ e.g. a mixture of 1 part X and 3 parts Y, is a ratio by weight.“QS” or“QSP” means sufficient quantity for 100 % or for 100 g. +/- indicates the standard deviation. All measurements are understood to be made at 23 °C and at ambient conditions, where "ambient conditions” means at 1 atmosphere (atm) of pressure and at 50 % relative humidity.“Relative humidity” refers to the ratio (stated as a percent) of the moisture content of air compared to the saturated moisture level at the same temperature and pressure. Relative humidity can be measured with a hygrometer, in particular with a probe hygrometer from VWR ^® International.

Herein“min” means“minute” or“minutes". Herein“mol” means mole. Herein“g” following a number means "gram” or“grams”.“Ex.” means“example”.

All amounts as they pertain to listed ingredients are based on the active level (‘solids’) and do not include carriers or by-products that may be included in commercially available materials. Herein, "comprising” means that other steps and other ingredients can be in addition. The compositions, formulations, methods, uses, kits, and processes of the present invention can comprise, consist of, and consist essentially of the elements and limitations of the invention described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein. Embodiments and aspects described herein may comprise or be combinable with elements, features or components of other embodiments and/or aspects despite not being expressly exemplified in

combination, unless an incompatibility is stated.“In a preferred embodiment” means that one or more embodiments, optionally ail embodiments or a large subset of embodiments, of the present invention has/have the subsequently described feature. Where amount ranges are given, these are to be understood as being the total amount of said ingredient in the composition, or where more than one species fall within the scope of the ingredient definition, the total amount of ail ingredients fitting that definition, in the composition.

The following acronyms are used herein: APEG 1100 or PEG-A 1100 or Polyglykol A 1100 = a-2-propen-1 -yl-io-hydroxypoly(oxy-1 ,2-ethanediyl) with a molecular weight of M _w =1 100g/mol; APEG 2400 or PEG-A 2400 or Polyglykol A 2400 = a-2- propen-1 -yl-u)-hydroxypoiy(oxy-1 ,2-ethanediyl) with a molecular weight of

Mw=2400g/mol; APEG 5000 or PEG-A 5000 or Polyglykol A 5000 = a-2-propen-1- ykj0-hydroxypoly(oxy-1 ,2-ethanediyl) with a molecular weight of Mw^SOOOg/mol; AS = acrylic acid; MAS - meth acrylic acid; APS ~ Ammonium persulfate,

SPS = Sodium persulfate, KPS = Potassium persulfate.

Unless otherwise stated, viscosity herein is measured at 23 °C in centipoise (cP) or mPa s using a Haake Mars III rheometer (Thermo Scientific).

“Molecular weight” or“M.Wt.”“Mw”,“M _w ” or“MW” and grammatical equivalents mean the weight average molecular weight, unless otherwise stated. Also relevant for the determination of the molecular weight distribution is the number average molecular weight“Mn”,“M _n ” and grammatical equivalents, and the polydispersity “D” or“PDI”.

Number average molecular weight: Mn

The number average molecular weight is the statistical average molecular weight of all the polymer chains in the sample, and is defined by:

where Ms is the molecular weight of a chain and Ns is the number of chains of that molecular weight. M _n can be predicted by polymerisation mechanisms and is measured by methods that determine the number of molecules in a sample of a given weight; for example, colligative methods such as end-group assay. If Mn is quoted for a molecular weight distribution, there are equal numbers of molecules on either side of Mn in the distribution.

Weight average molecular weight: Mw

The weight average molecular weight is defined by:

Compared to Mn, Mw takes into account the molecular weight of a chain in determining contributions to the molecular weight average. The more massive the chain, the more the chain contributes to Mw. Mw is determined by methods that are sensitive to the molecular size rather than just their number, such as light scattering techniques. If Mw is quoted for the molecular weight distribution, there is an equal weight of molecules on either side of Mw in the distribution.

The polydispersity index PDI is used as a measure of the broadness of a molecular weight distribution of a polymer, and is defined by:

The larger the PDI, the broader the molecular weight. A monodisperse polymer where all the chain lengths are equal (such as a protein) has an Mw/M _n =1.

The weight average molecular weight can be measured by gel permeation chromatography (GPC), also referred to as size exclusion chromatography (SEC). The molecular weight of polymers and its measurement is described in the textbook“Principles of Polymerization” by Georg Odian, third edition, Wiley- Interscience, New York, in chapter 1 - 4, page 19 to 24, ISBN 0-471-61020-8, The process to determine the weight average molecular weight is described in detail in chapter 3 of Makromolekulare Chemie: Eine Einfiihrung' ¹ by Bernd Tieke, Wi!ey- VCH, 2. vollstandig uberarbeitete und erweiterte Aufiage (3. Nachdruck 2010) ISBN-13: 978-3-527-31379-2, page 259 - 261.

Determination of molecular weight and distribution of Polymer samples by GPC was determines under the following conditions.

Column: 1x PreColumn 10pm (modified cross linked acrylate

copolymer)

1X 30 A 10 pm, 300 mm x 8 mm ID (modified cross linked acrylate copolymer) 1X 1000 A 10 mih, 300 mm x 8 mm (modified cross linked acrylate copolymer)

Eluent: 55 w% acetonitrile /45 w% water + 1 ,25 g/L Disodium

hydrogen phosphate

Detector: Rl

Oven temperature: 27 °C

Flow: 1 ml/min

Injection volume: 10 pi

Sample cone.: 5g/l

Solvent: 55 w% acetonitrile / 45 w% water + 1 ,25 g/L Disodium

hydrogen phosphate

Calibration: Polyethylene glycol standards in the range from

430 - 1 ,015,000 Dalton

“Water-soluble" refers to any material that is sufficiently soluble in water to form a clear solution to the naked eye at a concentration of 0.1 % by weight of the material in water at 25 °C. The term“water-insoluble” refers to any material that is not“water-soluble”.

“Monomer” means a discrete, non-polymerised chemical moiety capable of undergoing polymerisation in the presence of an initiator or any suitable reaction that creates a macromolecule e.g. such as radical polymerisation,

polycondensation, polyaddition, anionic or cationic polymerization, ring opening polymerisation or coordination insertion polymerisation.“Unit” means a monomer that has already been polymerised i.e. is part of a polymer.

"Polymer" means a chemical formed from the polymerisation of two or more monomers. The term "polymer" shall include all materials made by the

polymerisation of monomers as well as natural polymers. Polymers made from only one type of monomer are called homopoiymers. Herein, a polymer comprises at least two monomers. Polymers made from two or more different types of monomers are called copolymers. The distribution of the different monomers can be random, alternating or block-wise (i.e. block copolymer). The term“polymer” used herein includes any type of polymer including homopolymers and

copolymers.

“Derivatives” includes but is not limited to, amide, ether, ester, amino, carboxyl, acetyl, acid, salts and/or alcohol derivatives of a given compound. In a preferred embodiment,“derivatives thereof” means the amide, ether, ester, amino, carboxyl, acetyl, acid, salt and alcohol derivatives.

Examples

Polyglykol A is a polyalkylene glycol a!lylether.

Polyglykol A 2400 is a polyalkylene glycol alfylether with a molecular mass of 2400g/mol.

Polyglykol A 1100 is a polyalkylene glycol allylether with a molecular mass of 1100g/mol.

Polyglykol A 5000 is a polyalkylene glycol allylether with a molecular mass of 5000g/mol.

Polymerization process: General polymerization procedure in water

Dose in a 2-Liter Quickfit round bottom flask equipped with a refux condenser, two over surface gas inlet tubing connected with dosing pumps (e.g. Dosing pump A and Dosing pump B), inner temperature sensor and overhead agitator 579,30 g Polyglykol A 2400 according to Formula (B) is dispersed in 183,00 g distilled water. Inject nitrogen subsurface for 1h at agitation of 200 rpm. During this time the temperature of the reaction mixture is raised and stabilized to 80 °C with help of a water bath. 72,00 g Acrylic acid according to formula (A1 ) dissolved in

198,00 g distilled water (Solution A). Inject nitrogen subsurface for 15 Min at agitation of 200 rpm. Solution A is connected to Dosing Pump A. 2,88 g APS dissolved in 270,00 g distilled water (Solution B). Inject nitrogen subsurface for 15 Min at agitation of 200 rpm. Solution B is connected to Dosing Pump B.

Solution A and B are pumped separately with Dosing pump A and Dosing pump B into the reaction vessel. After a few minutes the start of polymerization becomes obvious due to the rising temperature. After complete dosing of Solution A and B the reaction solution is stirred for further 3 h and cooled down to room temperature. Adjust the pH at 23 °C with approx. 130,5 g of Sodium hydroxide solution (30 wt.-% in water) to a pH of 10,5.

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General procedure for the synthesis of the invention related paint fomulations

The invention related copolymers were tested at 0.14 wt.-% active concentration in a paint formulation as shown below in table 1.

For the comparative examples, state-of-the-art additive technology was used. As representative example of additives based on quaternary organic diamines, Cycloquart ^® from BASF (declared as polymer derived from N,N,N',N'-tetramethyl- 1 ,6-hexanediamine and 3 propylene oxide units) was used at 0.35 wt,-% active concentration in comparative example 1.

As example of a combination of amines and alkyl siliconates, Betolin A11 from Woltner (declared as a mixture containing potassium methyl siliconate, potassium hydroxide and potassium ethylenediaminetetraacetate) at 0.18 wt.-% active concentration and Betolin Q40 from Wo!lner (declared as

N,N,N ^' ,N ^' -tetrakis(hydroxypropyl)ethylenediamine) at 0.20 wt.-% active

concentration were tested in comparative example 2. In both comparative examples 1 and 2, Lopon ^® 890 (declared as sodium polyacrylate in water) at

O.14 wt.-% active concentration was used as dispersing agent (comparable to Hydropalat 5040 used in the paint compositions described in WO 2008/037382) TABLE 1 : Paint composition containing water glass

The rheological properties of the paint samples were investigated after preparation and after 28 days storage at 50 °C. The paint samples were characterized in a Haake Mars III rheometer (Thermo Scientific). Since sample history may significantly influence the results of the measurements, an accurate protocol was followed for sample taking, loading and pre-shearing in order to make sure that all samples had experienced the similar process immediately before the measurements started. A solvent trap filled with water and a cover were used to avoid solvent evaporation during the

measurements. The measurements were done at 23 °C. A cone (1° 60 mm)-plate geometry was used for the shear stress controlled measurements and a plate (35 mm)-piate geometry for the oscillatory measurements. A shear rate ramp between 1 and 200 s-1 was recorded and the value of the viscosity was taken at a shear rate of 60 s-1. The thixotropic behavior was evaluated by recording a shear rate ramp from 0.1 to 1000 s-1 and back. The area between the up and down curves was used as an indication of the thixotropy of the sample. Dynamic oscillatory measurements conducted applying a strain ramp between 0.1 and 100 % at constant frequency of 1.592 Hz were used to investigate the gel character the paints and the elastic modulus was determined from the linear plateau value of the curve corresponding to the linear viscoelastic region of the paint sample.

The better performance of the invention related samples in comparison to the state-of-the-art paint compositions is indicated by the smaller changes in viscosity over the storage test, which points to a better stabilization of the paint.

Furthermore, the samples do not show sedimentation or any symptom of phase separation after storage. The invention related paint samples show after storage smaller values of thixotropy, which is an indication of better workability. In addition, the elastic moduli of the invention related samples are lower, which indicates a weaker gel character of the paints and therefore a better stabilization of the waterglass during storage. The paint compositions with lower thixotropy and gel character show a better appearance and are better to handle and to utilize, therefore they bring a benefit for users in comparison to the state-of-the-art. ί_u i y v v W

29

TABLE 2: Rheological properties of the paint samples 3 o

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